Centrifugal separator



July 21, 1953 5, cox ET AL 2,646,172

CENTRIFUGAL SEPARATOR Filed Sept. 19, 1947- 4 Sheets-Sheet 1 JNVENTORS.fir'aJ/eg/ 6. Cox.

7207714.? Jl/a 77s.

July 21, 1953 Filed Sept. 19, 1947 B. G. COX ET AL CENTRIFUGAL SEPARATOR4 Sheets-Sheet 2 y 1953 B. G. cox El AL CENTRIFUGAL SEPARATOR 4Sheets-Sheet 3 Filed Sept. 19, 1947 .I 75 a lll IN V EN TORS ZraJ/ey aCox. 772077245 [ll 477.5. BY

5 v irro/avzy July 21, 1953 B. G. COX El AL CENTRIFUGAL SEPARATOR FiledSept. 19, 1947 4 Sheets-Sheet 4 INVENTORS.

G Z/ Cox, Y flames f arzat W OF/VZK Patented July 21, 1953 2,646,172CENTRIFUGAL SEPARATOR Bradley G. Cox, Saginaw, and Thomas Evans,Tuscola, Mich., assignors to Baker Perkins Inc., Saginaw, Mich., acorporation of New York Application September 19, 1947, Serial No.774,97

27 Claims.

This invention relates broadly to new and useful improvements incentrifugal separators of the type used primarily for separating themother liquor or sirup from sugar crystals.

In the manufacture of sugar, mother liquor is centrifugedfrom thecrystals, andthe latter are then washed with water to removeany liquoradhering thereto. Usually the crystals are permitted to accumulate to aconsiderable depth in V the centrifuge basket and are removed from time.to time by suitable mechanical strippers.

A curb ring is provided at the rim of the basket .to prevent thecrystals from spilling during the centrifuging operation. This curbringmust meet certain'rigid specifications and no entirely satisfactory wayof mounting it on the basket has heretofore been devised. For example,the curb ring must rotate with the basket to prevent undesirable heatfrom being developed due to friction between the parts. Further, thecurb rin must seal the rim of the basket during the centrifugingoperation but be readily removable so that the crystals can be easilystripped from the basket. The curb ring cannot be fastened directly tothe centrifuge basket, since it then interferes with the operation ofthe mechanical strippers.

The usual practice is to mount the rings on the stripper so that itmoves with the latter. However, the stripper is disposed'in the basketand the posts which support the curb ring prevent the crystals frombuilding up uniformly on the basket. As a result, the sugar crystalsdonot' deposit uniformly on the wall of the basket, the weight of thebasket is not balanced and a gymtory effect results during thecentrifuging operation. Further, the supporting posts intercept thestreams of sirup and wash Water charged to the basket and cause muchsplashing and unnecessary spillage.

An important object of the present invention is to provide a centrifugalseparator of the abovementioned character wherein the curb ring issupported in a novel manner by means outside up of sugar crystals in thebasket.

Still another object of the invention is to provide a centrifugalseparator of the above-men'- tioned character wherein the curb ring andits adjuncts in no way interfere with stripping of v the sugarcrystalsfrom the basket."

2 Yet another object of the invention is to provide a centrifugalseparator of the above-mentioned character wherein the curb ring isuniquely shaped and associated with the basket to prevent the syrup inthe basket from leaking over the top of the basket and mixing with thesugar crystals which'have been removed from the basket.

A still further object of the invention is to pro.- vide a centrifugalseparator of the above-mentioned character having novel means formaintaining the mother liquor and wash water separate from each other.

A yet further object of the invention is to provide a centrifugalseparator of the above-mentioned character which is more efficient inoperation and is capable of handling a greater volume of sirup than hasheretofore been possible. Other objectsand advantages of the inventionwill be apparent during the course of the following description.

In the drawings forminga part of this specification and wherein likenumerals are employed to designate like parts throughout the same:

' Figure 1 is a vertical sectional View through a centrifugal separatorembodying the invention and showing the centrifugal basket in itsnormal,

raised position;

Fig. 2 is a view similar to Fig. 1 but showing the centrifugal basketlowered to discharge the sugar crystals; l

Fig. 3 is an enlarged, fragmentary View of the portion of Fig. 2enclosed in the circle 3;

Fig. 4 is an enlarged, fragmentary, transverse sectional view taken onthe line 44 of Fig. 1, and particularly illustrating the construction ofthe centrifugal basket;

Fig. 5 is an enlarged, fragmentary view of the portion of Fig. 1enclosed in the circle 5;

Fig. 6 is an enlarged, fragmentary view of the portion of Fig. 1enclosed'in the circle 6 but showing the curb ring raised slightly fromcentrifugal basket; Fig. 7 is a vertical sectional view taken on theline of Fig. 1, particularly illustrating the spraying device forwashing out the centrifugal basket underneath the stripper;

Fig. 8 is an enlarged, fragmentary view of the i portion of Fig. 1enclosed in the circle 8;

Fig. 9 is an enlarged fragmentary, vertical sectional view showing amodified means for raising and lowering the curb ring; and f Fig. 10 isa diagrammatic'view showing the electrical network, hydraulic fluidlines, and water the piping which control, operate, and supply thecentrifugal separator.

Considered in certain of its broader aspects, the present inventioncomprises a centrifuge basket mounted in a suitable open framework 22and rotatably driven by a motor 24 through a vertical tubular shaft 26.Also mounted on the shaft 26 for. rotation therewith and fitting snuglywithin the basket 28 is a disk-shaped stripper 28. The stripper 28 isfixed on the shaft 26 against axial movement as well as againstrotation, and

the basket 20 is moved up and down on the shaft relative to the stripperby a fluid motorgfifl. ;Nor

mally the basket 20 is raised as shown in Fig. 1, so that the stripper28 is disposed at the bottom thereof; however, when sugarcrystals-accumulate to a desired depth in the basket, it is lowered tothe position shown in Fig. 2. .the basket 26 moves downwardly, thecrystals aresupported by the stripper plate 28 and spill overthe' top ofthe basket into an outer annular surrounding chamber-3|. 'From thchamber 3l,-the crystals are expelledby means "hereinafter described indetail into a dischargespout 32.

--A-slurry of sirup and sugar crystalsis charged to-the-basketifithrougha pipe'34 controlled by a-charging valve, not shown, and thecontents are preventedfrom' spilling over the top of the basket by acurb ring 36. Th valve conveniently may be a valve-of the-type showninour copending application Serial No. -772,367'which was filedSeptember5, 1 947. The charging operation may be accomplished-while'thebasket 20 is rotating at relatively high speed and the liquor or sirupis thrown outwardly bycentrifugal-force through the foraminous verticalwall of the basket into an inner annular surrounding chamber 38. Thecurb ring -36 is supported by-the stripper 28 through rods 40 and 42 anda connecting ring 44. The stripper '28 drives the curb ring 36 atthe-same rotative speed as the basket:28 and holds it axially fixed atall times. When thebasket 2t 'is-fully raised, the open "top thereof ispressed solidly against the under surface of-curb ring 36 which sealsthe basket at-the rim and prevents the contents of the basket fromspilling. However, when the-basket-21l is lowered, it drops awayfromthecurb ring 36, so that'the sugar crystals can be stripped ordischarged over the top of the basket inthe manner hereinabovedescribed. After-the sugar 'crystals'have accumulatedto the desireddepth in basket 20, fiowthrough the supply pipe 34 is'shut off by meanshereinafter describedin detail and the crystals in the basket aresubjected to a water rinse. Wateris introduced into the basket'through apipe 46-which extends downwardly between the drive shaft "26 and. thecurb ring 36. The rinsewater is thrown outwardly from the basket 20 intothe chamber 38 by centrifugaLfOrce-in the same manner as the motherliquor. This water washesaway any sirup still adheringto the crystalsinthe basketlfl and also. cleans the basket .and the walls of thesurrounding chamber 38.

. Both the mother liquor and the rinse waterare discharged from thechamber 38 through a port 48. However, the mother liquor is subjected tofurther processing, and it is therefore desirable that it be collectedseparately from the rinse water. In order to accomplish this result,concentric annular housings 50 and 5| are mounted around the lowerportion of chamber 38 which housings have chambers 52 and 54 providedwith inner annular inlets 56 and 58. Theouter housing 50 is fixed andthe inlet is positioned to .5! is lowered, as shown in Fig. 1, duringthe charging operation, so that the mother liquor is -.c0llectedin theouter chamber 52 and raised .during the rinsing operation to theposition shown in-Fig. 8, so that the rinse water is collected intheinner .chamber 54. discharged from chamber 52 through an outlet Themother liquor is 1.60:1forgfurthermaprocessing and the rinse water isdischarged from chamber 54 through an outlet 62 to any suitable place ofdisposal.

From time to time during operation of the separator it is necessary towash betweenthe bottom of -the'-bask-et-2-9 andthe stripper -28-toremove sirupand occasional sugar crystals which by-pass' the stripper.To this end, a wash-pipe 84 isarranged vertically below the basketZB-With the discharge end thereof facing upwardly toward the-bottom ofthe basket. The stream of water-frompipe fidis collected in a downwardlyopening, annular groove 56 provided-in the bottom of thebasket 20 andpasses upwardly into the basket through a series ofpassages 68. In thisconnection,-it will be observed that the annular groove -56 isformedwith an upwardly and outwardly inclined outer wall T0 and that thepassages -68 extend upwardly from this wall. As a result of thisarrangement, substantially all the water-discharged by pipe 64 passesinto the basket 28, and-very little water is lost as overflow orspillage.

The-pipe64 is carried by a fluid motor 12 which moves it verticallyrelative to the basket 26. This is necessary, sincethe outlet of pipe 64should be disposed in close proximity to'the bottom of the basket '20during the washing operation; however, during normal operation of theseparator, the pipe 64-mustbe positioned a considerable distance belowthe basket in order not to interfere with vertical-movement of thelatter.

Certain details of construction not readily apparent from the abovegeneral description are now given.

.Theba-sket 26 has a generally disk-shaped bottom "14 and a foraminouscircular side wall 76. The latter is provided with a lining whichfilters the sugar crystals and permits the basket to slide easily on thestripper 28.

As perhaps best shown in Fig. 4, the lining comprises aplurality ofsimilar vertically spaced wire rings 18 which fit snugly within thevertical wall 16 and fitted over each ring is a band 88 of sheet metalor the like. As shown in Fig. 5, each band 86 is essentially V-shaped intransverse section'and is arranged with the flange portions thereof inembracing relation to its respective ring I8. Also, it will be observedthat the bands ,89 project substantially beyond the wires '58, and theprojecting portions thereof are notchedto receive the vertical bars 82.Bars 82 are uniformly spaced-and the spacing issuch that thesugarciystals are retained but the liquor andrinse waterpass readilytherebetween. Also, theinner vertical surfaces 84 of the bars 82 areflatand smooth .toslidably engage the stripper 28. In this connection,it will be observed that carrier bands 80 so that the'peripheryfof thestripper 28 engages only the vertical surfaces 84 and is not required topassover anyintersecting transverse members during vertical travel ofthe basket 20. Also, the, smooth surface presented bythe vertical strips82; facilitates removal of the sugar crystals from the basket. I I

Thevertical drive shaft 26 extends axially through the basket. 20, andthe bottom I4. of the basket is formed with. a centrally locatedupstanding boss 86 through which the shaft passes. A stuifingbox 88 onthe boss 86 and surrounding the shaft 25 provides a fluid tight sealbetween the basket and the drive shaft. Drive shaft zepreferably iscoupled to the motor 24 by a universal joint 96 and is'journaled forrotation in upper and lower bearings 92 and 94.

The upper bearing 92 "conveniently canbe attached to an overhead portionof the framework 22. An unbalanced load in the basket 20 oc-' casionallycauses a gyratory effect; and, according to the present invention, thisphenomenon is compensated by mounting the lower bearing 94 for-freefloating movement in a guide 96 which in turn is fastened to bottommembers of the frame 22. As a result ofthis construction, the lowerbearing 94 is permitted to gyrate'freely within limits defined by theguide 96.

As suggested, the basket 20 is fixed to the shaft 26 and is movablevertically on the shaft .by the fluid motor 30. Specifically, theoylinder'eb of the motor 35} is arranged concentrically around the driveshaft 26 below the basket 2'3,

and the upper end thereof abuts against and is welded or otherwise fixedto the bottom it. Thus, the bOttOII'L'TQ- closes and the stuffing box 88seals the upper end of the cylinder 98. A piston I90 is keyed, as atI02, to the cylinder 98 and as at I94 to the drive shaft'ZG. The key I04connects the piston Illil to the drive shaft 23 for mutualrotation, andthe key I82 connects the piston to the cylinder 98 for mutualrotation;however, the key IE4 axially fixes the piston on the drive shaft,whereas the key I02 is freely slidable in a guideway Iil'u which extendsthe full length of the cylinder 93. Thus, the drive shaft 26 rotatablydrives the basket 26 through thev piston I30 and cylinder 98 andhydraulic pressure admitted to one side or the other of the piston willraise or lower the cylinder 98 and basket 25 as aunit on shaft 26.

According to the present invention, hydraulic fluid is supplied to themotor 33 throughthe shaft 26 to raise and lower the centrifugal basket20. More s ecifically, a pipe I88 is mounted concentrically in thetubular shaft 26, which pipe extends from the upper bearing 92 to apoint below the piston I09 and is sealed at its ends to the shaft 2E5.Hydraulic fluid is admitted into the shaft 26 above the pipe Itiithrough an inlet H2, and this fluid is conducted downwardly through thepipe I38 to discharge ports I I4 which open into the cylinder 98 belowthe piston Illil. Also, hydraulic fluid may be introduced into the vannular space IIIi between the shaft 26 and pipe inlet, I12, fluidpressure in the cylinder 98 below piston I00 will move the cylinder andbasket 20 downwardly on the shaft 26. On the other hand, if valve I22 isoperated to direct hydraulic fluid to inlet II8, fluid pressure in thecylinder 98 above piston I00 will move the cylinder'and basket 20upwardly on shaft 26. Thus, by proper operation of the control valve I22, the basket may be raised or lowered periodically withoutinterrupting or checking the rotative speed of the basket. I

The stripper plate. 28 also is formed with a central boss I24 throughwhich the shaft 26 passes and which is fixed to theshaft againstrotation by a key I26. An annular shoulder I28 formed on shaft 26 belowthe stripper 28 and a collar I38 fixed on the shaft above the stripperby member I3I co-op-erates to hold' 'the latter axially fixed on theshaft. Thus, stripper plate 28 rotates in unison with the basket 26.How'- ever, when the basket 28 is lowered, crystals sup ported by thestripper 28 spill over the topof the basket into chamber 3 I.

The particular shape of the curb ring 36 and the manner in which it isassociated with the basket 26 comprise an important feature of theinvention. As perhaps best shown in Fig. 5, the inner annular portionI32 which projects radially inwardly across the basket 20 is downwardlyoffset to define a radially outwardly facing annular surface I34 whichsnugly fits an inturned flange I36 on the rim of the basket 20. Further,it will be observed that the surface I34 extends downwardly below theflange I33 to define an annular pocket I38, and'this pocket communicateswith an annularseries of holes I40 which are provided in the side wallof the basket immediately below the flange I36. By reason of this uniqueconstruction, the mother liquor or sirup is prevented from leakingbetween the curb ring 36 and the rim of the basket 20. Any

sirup which tends to crawl up the side wall of the basket ischecked bythe inturned flange and tends to accumulate in the pocket I38. Insteadof working through the relatively tight joint between the basket 20, andthe curb ring 36, the sirup follows the path of least resistance andfiows outwardly through the holes I 40. In this connection, it will beobserved that the holes- I40 dischargethe sirup into thesurroundinginnerchamber 33 and the sirup is then disposed of in the manner hereinabovedescribed." Also, it

ring 36 is supported outside the basket '20 is another important featureof the invention. By reason of this construction, the supports areunobstruotively positioned, and atthe same time the curb ring isproperly supported to rotate in unison 'with the basket 20 and stripper28. Also, the curb ring effectively seals the top'ofthe basket andprevents leakage of sirup therefrom during the centrifuging operation.However, by

' reason of the unique manner in which the basket 20 and curb ring 36are combined and correlated, the basket drops away from the curb ringduring the discharging operation so that the crystals are readilyexpelled over the. top of the basket;

The chamber. 381which;is disposed immediately 'aroundzthe basket 29 isformed :by concentric walls .Id2 and I6.

The inner wall 1A9 depends from the basket 29 and the upper'edge thereofis formed with a horizontal flange. :46 which overlies and is spotwelded or otherwise:fastened .to .anoutwardly extending flange I49 on'the basket.

Atits loweredge, the wall I44 is formed with an outwardly extendingflange I59whichsupports an inwardly extending flange I52 .on the outerwall I42. The wall. i 52 extends tothe top of the'basket 29 and has aninwardly extending .flange I54 which fits snugly around the rim of -48serves this sump.

The housings 59 and I are concentric to'each other and are U-shape'd intransverse section, as shown in Figs. 1 and 2. The outer'vertical wallsof housings 59- and 5! extend above the inner walls thereof, and bothouter walls are provided with angularly, inwardly andupwardly extendingcovers I56 and I53. In this connection 'it will be observed that thecover I56 pro-iects radially outwardly beyond the inner housing .5! andthat the projecting eave' portion thereof pro jects over the inner wallof the outer housing 59 to seal the same. Also, it will be readilyapparent from the drawings that the. inlets 56 and 58 of chambers 52 and54 are formed by merely extending the outer wall of each housing 53 and5I above the inner wall thereof.

The wash-water housing 5I is raised to bring inlet 58 into register withoutlet port =58 by a series of levers I64 which are iulcrumed to theframe .22 and preferably are operated by a hydraulic cylinder I60 (Fig.

The crystal chamber 3! is formed byan annular sheet-metal housing I66having an outer vertical wall- I 68 provided at the upper edge thereofwith an inwardly extending annular flange I19 which terminates adjacentto and just below the periphery of curb ring 36. Housing I66 isstationary and is secured in any suitable manner to the frame 22. Thebottom of housing I66 is separate from the vertical side wall I66 andcomprises an annular plate I'I2 having a short, up-

standing, circular wall I14 at the inner edge thereof and adjacent theouter wall I42 of liquor chamber 38. Plate I12 is supported for rotationby sets of vertical and horizontal rollers I16 and I18 (Fig. 3). Eachset of rollers is carried by a supporting bracket I89 which is fastenedto and depends from the outer vertical wall I69 of housing I66. Belowand fixed to the plate I72 is a pulley I82 which is rotatably drivenby'a motor I84 through endless belts I86. Motor I84 rotates the plateI'I2 relatively slowly. Sugar crystals discharged into chamber 3| frombasket 29 fall onto the rotating bottom plate I12 and are pushed ofi theplate into discharge spout 32 by a plow or baiile I88 which is carriedby and projects radially, angularly inwardly from the wall I68 acrossthe plate I2 (Fig. 2).

Any sirup or wash water which may drip onto the curb ring 36 or anycrystals or sirup from the basket 29 which may overflow the curb ringare thrown by centrifugal force into a housing I99 which surrounds theupper part of the crystal housing H66. The housing I99 comprises avertical circular wall I92 arranged concentrically to and spacedcircumferentially from the wall I68 so that the latter wall, in effect,partitions the overflow chamber from the crystal chamber 3|. At thelower edge thereof, the wall I92 is formed with an inturned flange I94which is secured to the wall I68, and at the upper edge thereof the wallI92 supports a cover I96 having a central opening I98 through which thedrive shaft 26, sirupsupply pipe 34, and wash pipe 46 extend. Atthebottom of housing I99 is a discharge pipe 299 which conducts anymaterial thrown into the-housing back into the'process.

For a, detailed description of the wash pipe 64 and fluid motor I2,attention is directed to Fig. '7. It will be observed that fluid motorI2'comprises a cylinder 292 and a piston 294 mounted for reciprocationin the cylinder. The lower end of cylinder 292 is closed by a plate 296and the upper end thereof is closed by a plug 299. Wash pipe 64 extendsthrough and is slidably suported by the plug 298, and the end thereofwithin the cylinder 292 is fixed to the piston 294. Astuffing box 2I9carried by the plug 298 provides a fluid tight seal with the pipe 64.The piston 294 has a central aperture 2I2 which opens through theside'thereof and communicates with-the spray pipe 64. A gauge tube 2I4is welded or otherwise fixed on the upper face of the piston 294 andabuts against the closure plug 296 to limit upward movement of thepiston 294 in the cylinder 292.

Hydraulic fluid is delivered to the cylinder 292 below piston 264through a pipe 2I6 connected to the plate Also, hydraulic fluid may besupplied to the cylinder 292 above the-piston 294 through a pipe 2I8which opens through the side of the cylinder immediately below the upperclosure plug 268. When the piston 294 is at the upper limit of itstravel, aperture 2I2 communicates with a pipe 229 which is screwed intothe side wall of cylinder 292; and-the pipe 229 is connected to a secondpipe 222 through a check valve 224 which permits liquid to flow frompipe 222 to pipe 229 but prevents reverse flow therethrough. Pipe 222also is screwed into the side wall of cylinder 292 and is locatedimmediately below the piston 299 when the latter is fully raised asshown in the drawing.

As suggested, the wash pipe 64 normally is lowered so as not to obstructvertical travel of the basket 29. Therefore, in use, the first operationis to admit hydraulic fluid into the cylinder 292 through pipe M6 toraise the piston 294 to the position shown in Fig. 7 and to position thedischarge end of wash pipe 64 in proximity to the basket 29. Hydraulicfluid admitted into cylinder 292 below piston 294 causes the latter torise until it is stopped by the gauge tube 2I4. When the piston 2%,reaches the upper limit of its travel, it establishes communicationbetween the cylinder 262 below the piston 294 and pipe 222. Hydraulicfluid then flows through pipe 222,

valve 22% and pipe 229 to the central aperture H2 and thence passesupwardly through wash pipe 64 which discharges it against the bottom ofthe housing in the manner hereinabove described. After the washingoperation is completed, flow through pipe 2I6 is stopped and hydraulicfluid is admitted into the cylinder 292 above piston 296 through pipe2I8. When piston 294 moves downwardly sufliciently to establishcommunication between the cylinder above the piston and pipe 229, checkvalve 224 automatically closes to prevent fluid from entering thecentral aperture 2I2 and locking thepiston.

59 An alternative structure for supporting the curb ring 36 is shownin'Fig. 9. I In the modified form of the invention, the supporting rods42 are operated in unison by fluid motors 226 to raise and'lower thecurb ring'36. As shownin the drawings, the rods 42 extend axially intothe motor cylinders 228 through stufiing boxes 236 and-are fastened topistons 232 which operate in the cylinders. Cylinders 228 convenientlymay be, fastened to the bottomof the liquor housing Hydraulic liquid issupplied to the cylinders 223 alternately through pipes 234 and 236;andthe operation is timed so that the pistons 232 are raised suflicientlyto lift the curbring 36 from the basket 28 as shown in Fig. 6 justbefore the basket is lowered. In operation, the curb ring '36 may bereturned to its closed position either before or after the basket 26 israised to its charging position.

Reference is now had to Fig. 10 which shows the hydraulic and freshwater circuits for the separator as well as the electrical networkforoperating the various parts of the separator automatically and inpropersequence.- I

A pump 240 driven by motor242 draws hydraulic liquid from a tank244through an inlet pipe .246 and discharges the same through an outletpipe 248, Which outlet pipe supplies liquid under pressure to variousfluid motors which operate .the movable parts of the separator.

In this connection, it will be observed that the charging valve 35 isoperated by a fluid motor .250 and that the latter iscontrolled by asolenoid operated reversing valve 252. In the drawing, valve 252 isshown positioned to retract the piston in fluid motor 258 whereby toclose the charging valve35. However, it will be readily apparent that ifvalve 252 is moved to the right,

as viewed in the drawing, hydraulic liquid;from

line 248 will advance the piston in fiuidmotor 258 and openthe chargingvalve 35. Hydraulic liquid forced from fluid motor 250 during operationof the same passes through reversing valve 252 and is conducted to apipe 254 through either of pipes 256 or 258 depending on the position oftheva-lve. Pipe 254 returns the-liquid to tank .244. a

draulic liquid under pressure passes from the supply pipe 248 throughpipe 268to a solenoid operated reversing valve 262 and thence flowsthrough one of pipes 264 or 266 to the fiuidmotor .168.

other of pipes 264 and 266 and this liquid flows to the return line 254through apipe 212.

- In connection with the operation of basket 26, hydraulic liquid isconducted from the supply pipe 248 to the valve I22 through pipe'2'I4.Communication is established between the valve 422 and the motor 38which operates the basket in the manner hereinabove described, andliquid To operate the wash water housing 5|, hy-

Manifestly, actuation of motor I60 causes fiuid to be returned to valve262 through the ducts hydraulic fluid from the pressure side of I thepump 248 back to the tank 244 through a pressure relief valve 284. Thepressure relief valve'here shown is of the balance piston type and iscontrolled by a solenoid operated valve 286, which valve 286 in turncontrols flow of hydraulic liquid through a second by-pass 288 betweenthe main return pipe 254 and the relief valve 234 in the conventionalmanner.

Fresh water is supplied to the wash and backwash pipes 46 and 64,respectively, from a suitable source of supply here indicatedas a tank235. Specifically, a pump 292 driven by a motor 234 draws water from thetank 290 through inlet pipe 236 and discharges the same through anoutlet pipe 236 which connects with branch pipes 380 and 362. Branchpipe 38!] leads to a solenoid operated reversing valve 364 whichcontrols pipes 366 and 368 leading to the fluid motor I2 which actua'testhe backwash pipe 64. Return liquid from the fluid'motor I2 passesthrough the reversing valve 384 and thence through pipe Sid back to thetank 230. The other branch pipe 362 is controlled by a solenoidoperated. valve H2 and leads directly to the wash pipe 46.

A. plurality of normally open mercury-type switches SI, S2, S3,,S4, S5and S6 are closed in predetermined sequence by cams 3M, 3I6,, 3I8, 326,322 and 324 to operate the various mech anisms of the separator inproperly timed, sequential relation, and a timer motor 326 rotates thecams 3I4-32LI in unison and. at proper speed.-

its control panel'and indicates when the motor 326 is energized.

As soon as the first switch SI is closedby cam 3M, a circuit is closedthrough a control relay CRI, which relay is connected acrossv the powerbusses 328 and 336 and in series with the. switch SI byconductors'340,342, 344 and 346. Relay CR! operates two normally openswitches SW! and. SW3 and a normally closed switch SW9. Switch SW!controls aconductor 348 which connects an auxiliary timing device 358across the power busses 328 and 336. The normally closed switch SW9 alsocontrols the conductor 332 and thus the operation of the motor 326. Thepurpose of switch SW8 will be hereinafter described in'detail. Whenrelay CRI is energized, it closes switch SW7 and opens switch SW9. outthe motor 326 to stop rotation of cams 3I4I This drops 2324' and cuts'inthe auxiliarytimer 358 which controls the circuit for a predeterminedperiod of time and then mechanically reverses the switches SW7, SW3 andSW9 in an obvious manner by means ofarm 35! to again start the motor 326in operation. v

Normally open switch SW8 controls a conductor 352 which connectssolenoid VI across the power busses 328 and 336 and the solenoid VIoperates the reversing valve 252 which controls the charging valve 35.When switch SW6 is closed by energization of relay CRI, the solenoid VIis energized to operate reversing valve 252 and to open the chargingvalve 35. Sirup is then charged tot'he basket 28 continuously until theauxiliary timer 350 completes its cycle of-operation and returnsitheswitch toits normal open position. Thus the basket 23 receives apredetermined charge of'sirupand crystals .for each operation of thevalve 35 and'the cycleis timed so that the basket is substantially fullycharged during each operationof the valve.

As: a safety feature to prevent overcharging of :the basket 20. due tochanges in viscosity of the charged material or other factors,the'basket' is equipped with a float valve S lli which controls aurelayCR2 connected across the power busses 328'and 333* by a con'ductor" 354.Relay CR2 operates'a normally closed'switch SW1 inconductor 352' and anormally open switch SW12 in a conductor. 353which joins'conductors 352and 35d. If the liquid level in the-basket 20 rises sufficientlyto'operate the float valve SIB before the auxiliary timer 35D closes thechargingvalve 35, relay CR2 is energized, switchSWl l is openedandswitch SW12 is closed. As soon as switch SWH opens, the circuit throughsolenoid" Vi is broken and the reversing valve 252 is actuated to closethe charging valve 35. Simultaneously, switch SWil closes a holdingcircuit which maintainsrelay CR2 energized even though the liquid levelin-basket 20 drops suiiiciently to open the float valve S13 and untilthe auxiliary timer 35B-completes its cycle of operation to returnswitches SW1, SW8 and SW9 to their normal positions. Manifestly, whenswitch SW8- is opened. by the auxiliary timer 353 the holding circuitthrough relay CR2. is broken and switches :SWI l and SWl2 return totheir normal positions preparatory to the next operating cycle.

When the timer motor 323 is energized by closure of switch SW9, cams3l4324 again begin to rotate. A short drainage period is. provided afterthe charging operation to permit the sirup to be centrifuged from thehousing and cam 3l6then closes switch S2 to complete a circuit throughthe solenoid'V2 which is connected across the main busses 323*an-d-330by a conductor 358. Solenoid V2 operates the reversing valve 332 whichdirects fluid to the motor Hill to raise the wash water housing 5|.

Shortly after switch S2 is closed cam 322 closes switch S5 to complete acircuit through solenoid V5 which is connected across the main busses328 and 330 by a conductor 363. Solenoid V5 opens valve 312 so thatwater is charged to the spray pipe 46 to wash the crystals collected inbasket 20. After a suitable interval, switchSB is released by cam 322 toshut off the'wash spray and the timer 323 then allows a short periodfordrainage.

At approximately the time the wash spray shuts off, cam 324 closesswitchS6 to complete a circuit through solenoid -V6' which is connected acrossthe main busses'323 and 336 and in series with theswitch by a conductor362. Energization of solenoid V6 opens the by-pass valve 286 so thathydraulic fluid flows in a short open circuit. As a result, pressure inthe hydraulic circuit drops so that the pump Mil-and motor 242 merelyidle and consume very little power.

At'the'end of the drainage period; switchSG is released by cam 224 tode-energize solenoid V6 and 1 close by-pass'valve 288 so that pressurein the. hydraulic -fluidline returns to normal. At aboutthe sametime-cam3H5 releases switch S2 to de-energizesolenoid V2, whereby to lower thewash water housing-5l to its-normal position so that the discharge port48 again registers with the sirup housing 50.

'Asthe'next step in'the operation cycle, cam 3'l8jclosesswitch S3 tocomplete a circuit through solenoid V3 whichis connected across the mainbusses 228 and 230and in series-with the'switch by a conductor 364.Energization of solenoid 'V3 positions. the valve I22 so that hydraulicfluid underpressure operates fluid motor 30 to'lower basket 20 wherebyto discharge crystals from the basketinto the crystal housing. 63. Afterdischarge. of the crystals is completed, cam 3l8 releases switch S3 totie-energize solenoid V3 whereby to: return thevalve I22 to its normalposition and to raise the basket 20preparatory tor-another chargingoperation.

At'about the time the basket 20 is fully raised, cam 3l4 again closesswitch SI to repeat the cycle of operation described above. This samecycle of charge, wash, drain and discharge may be repeated overand overagain entirely automatically as long as desired.

As: suggested, the: apparatus also includes means for operating thebackwash pipe 64 periodically to flush away sirup and crystals whichaccumulate in the basket 20 below stripper 23. Since sirupand'crystalsunder the stripper 28 tend to impair the operating efficiency of theseparator,-it is desirable that the washing operation be performedautomatically after the machine has cycled a predetermined number oftimes. In the apparatus here shown, a selector switch Sl3 isconnected'in the circuit, which selector switch controls thebackwashoperation, andis manually adjustable to cause the operation-to'occureveryone to" ten cycles of the machine. In the drawing'the selectorswitch S23 is set to cause the backwash operation to occur during everysixth cycle of the machine.

More specifically, the selector switch S53 has two series of tencontacts each designated generally at A and'B, respectively. Thecontacts in each set "are "arranged in" a generally circular pattern andcorresponding contacts in the two sets are electrically connected.Electrically conductive arms 3E4 and 36B are rotatably mounted to sweeprespective sets of'contacts A and B. Arm 354115; manually rotatable andcan be positioned to-engage any contact in the series B. On the otherhand, the contact arm 335 is mechanically operatedby a pawl and ratchet368 and 31D. Pawl 358 is-urged against the ratchet 310 by a spring 37!!and is actuated by a relay R! which is'connected across the main busses328 and 330 and in series with switch S! by a conductor 312. Ratchet31l)rotates against the action of a spring 314, and a slidable stop bar 316is urged against the ratchet by a spring 318 to prevent spring 314 fromreturning the ratchet 310 to its initial position after eachoperation'of pawl 365. Also, it

will bo -observed that the stop bar 375 is provided with" an upstandinglug 383 which extends upwardly-atone side of a laterally projecting pin382 on pawl 368. This arrangement permits axial movement of pawl 338 torotate ratchet 370 without disturbing the stop bar 316; however, thestop bar can be retracted to disengage pawl 358 from the ratchet so thatspring 314 can return the ratchet to its normal position. According tothe present invention, the stop bar 316 is retracted'bya' bell crank 384which in turn is actuated by a relay R2.

Thus, it will be readily apparent that relay R! willbeenergized eachtime switch SI is closed, i. e., once during each cycle of the machine,and that the arm 365 will be moved one contact in a counterclockwisedirection each time the relay R1 is energized. Whenarm 366 is rotated asufiicient number of times to close a circuit through the switch S13 toarm 364, the backwashing operation is caused to occur. With the switchS13 set as shown in the drawing, the machine must cycle six times tomove arm 366 from the full to the dotted line position before anelectrical circuit is completed between arms 364 and 366.

According to the presentfinvention, the switch S13 is connected in thenetwork with arm 366 electrically connected to bus 328 and in serieswith switch S4 by a conductor 386, and arm 364 is electrically connectedto the main bus 336 by a conductor 388. Thus when arms 364 and 366 arepositioned to close the circuit, current will flow through switch S13 assoon as cam 320 is rotated to close switch S4. In this connection, itwill be readily apparent that switch S4 is closed once during each cycleof the machine but current does not flow through switch S13 until arms364 and 366 are positioned to close a circuit through the switch.

' In order for switch S13 to control the backwashing operation, a relayCR3 is inserted in conductor 368, which relay has four normally openswitches SW14, SW15, SW56 and SW11. Switch SW11 is electricallyconnected across the main busses 328 and 339 and in series with asolenoid V4 by a conductor 396. Solenoid V4 actuates the reversing valve394 which controls fluid motor 12 for actuating and charging wash pipe64.

Thus, relay CR3 is energized whenever switches S4 and S13 are closed andenergization of the relay closes contact SW1! to complete a circuitthrough solenoid V4 to perform the backwashing operation. In thisconnection. it is to be understood, of course, that cam 32!! ispositioned to close switch S4 sometime during the cycle when the basket20 is raised.

In order to permit the switch S13 to be reset automatically after eachbackwashing operation, relay R2 is electrically connected to conductor388 between switch SE3 and relay CR3 by a conductor 392 and to the mainbus 339 in series with switch SW16 by a conductor 394. Also, a holdingcircuit is provided for relay R2 through switch SW by a conductor 396.Manifestly, energization of relay CR3 also closes switches SW15 andSW16, and closure of the latter switch energizes relay R2 to retractstop bar 3'56 and reset switch S13 in the manner hereinabove described.As suggested, closure of switch SW15 completes a holding circuit throughrelay CR3 so that the latter is not de-energized when spring 314 returnsarm 366 to its initial position during the resetting operation.

Normally open switch SW i 4 is connected across the busses 328 and 336and in series with solenoid V2 by conductor 396. Thus, solenoid V2 isenergized to raise the wash housing 5i each time relay R3 is energizedwhereby the backwash water is collected in the wash housing 51 and doesnot contaminate sirup'in the housing 59.

In order to prevent the backwashing operation from occurring, throughsome inadvertence, when the basket 26 is lowered, a relay CR4 isconnected in parallel with solenoid V3 by conductor 400.

Relay CR4 has a normally closed switch SW18 in conductor 388 and inseries with relay CR3, thus if solenoid V3 is energized for any reasonto lower housing 20 whenswitches S4 and S9 are closed,

from being completed through solenoid V4 to perform the backwashingoperation.

A backwashing operation can be performed manually at any time by meansof a normally closed push-button switch $19 which is electricallyconnected in conductor 388 and in series with switches S4 and S13 andrelay CR3. Also, switch S19 is adapted to close a circuit through a'conductor 402 which is connected to bus'328 and to conductor 388 betweenswitch S13 and relay CR3. Thus, manipulation. of switch S19 by-passesswitch S4 and selector switch S13 and closes a circuit through relay CR3to perform the backwashing operation. Switch S19 is normally positionedas shown in the drawing by spring 4114. Consequently, it must be helddepressed until the backwashing operation is completed. As soon as theswitch S19 is released, it is returned to its normal position by spring494 to de-energize relay CR3.

It is to be understood that the form of the invention herewith shown anddescribed is to be taken as a preferred example of the same and thatvarious changes in the size, shape and arrangement of parts may beresorted to without departing from the spirit of the invention or thescope of the appended claims.

Having thus described the invention, we claim:

1. In a centrifuging apparatus, a rotatable,

. axially fixed stripper member; a curb ring carried by and rotatablewith said stripper member;

and a basket mounted for rotation with and axially slidable on saidstripper, said basket provided at the rim thereof with an inturnedannular flange and said curb ring formed with an external annularshoulder which snugly fits and projects below said flange in oneposition of the basket, the projecting portion of said shoulder and theside wall of the basket cooperating to define a pocket below saidflange; and means for draining liquid'from said pocket radiallyoutwardly through the wall of the basket.

2. In a centrifuging apparatus, a rotatably driven centrifuge basket; acasing for receiving material centrifuged from the basket and providedwith a discharge port; and separate sirup and wash housings around saidcasing, each of said housings being annular in form and provided with aninlet disposed in confronting relation to said discharge port, saidsirup housing being stationary and normally arranged with its inlet inregister with said discharge port and said wash housing being verticallymovable to position its inlet in register with discharge ports and toclose the inlet of said sirup housing.

3. In a centrifuging apparatus, a rotatably driven centrifuge basket; acurb ring seating against the rim of the basket and rotatable therewith, said curb ring having a radially outwardly projecting portion; andan overflow housing around said basket, said housing having an innerannular wall provided with a radially inwardly extending ,fiangedisposed in alignment with and' spaced circumferentially from the rim ofsaid curb ring and provided about saidfiange with an annular inlet,whereby overflow from the basket or material charged, to the basket andfalling on said curbring is thrown radially outwardly by centrifugalforce from the curb ring and into said housing.

4. Ina centrifuging apparatus, a rotatably driven centrifuge basket; acurb ring seating against the rim of said basket; a housing around saidbasket having an internal annular partition defining concentric innerand outer chambers and said partition provided at theupper edge thereofwith an inturned annular flange disposed in alignment'with and in slightcircumferentially spacedirelation to theperiphery of said'curb ring;means for raising-and lowering the basket relative tosaid curb ring; andmeans for stripping solids from the basket upon movement of the latter"axially away from the curb ring, said stripper operable to'spill solidmaterial over the rim of the basket and into the inner of said chambersand said inturned annular flange serving as a bafile to deflectliquidoverflowing from the basket or falling onto said curb ring intothe outer of said chambers and to prevent such liquid from entering theinner chamber and contaminating said solid material.

In a centrifuging apparatus, a rotatable basket having aforaminousannular side wall; a curb ring surmounting said basket and seatingdownwardlyagainstthe rim thereof; a plurality of fluid actuated meanseach having amovable wall; and means disposed exteriorly of said basketconnecting said 'movable walls to said curb ring, whereby operation ofsaid fiuidactuated means effects independent relative movement betweenthe basket and saidcurb ring.

6. In a centrifuging apparatus, a rotatably driven centrifugebaskethaving a bottom; a stripper fitting snugly within the basket and axiallymovable relative thereto; and means for flushing between the stripperand the bottom of the basket including a wash pipe arranged to impingea'stream of .water upwardly against said bottom, and means associatedwith said bottom for collectingthe water impinged thereagainst and fordischarging it into the space between the bottom and said stripper;

' 7. In a centrifuging apparatus, a rotatably driven centrifuge baskethaving a bottom; a. stripper member snugly fitting in said basket andmovable axially relative thereto; and'means for flushing between thebottom of said'basket and said stripper including a wash pipe having adischarge outlet positioned to direct a stream of water upwardly againstsaid bottom, and an an- I nular groove in the bottom of said basketpositioned to receive said stream of water and provided with a=pluralityof passages effecting communication between said groove and the spacebetween said bottom and said stripper.

81 The combination as set forth in claim '7 wherein said groove has anoutwardly and upwardly inclined outer wall portion.

9. Ina centrifuging apparatus, a basket having a bottom and a foraminousannular sidewall; a generally disc-shaped stripper member 'within saidbasket and peripherally engaging the'inner surface of said annular sidewall; means for ro tatably driving the basket and stripper in unison;means for reciprocating the basket axially relative to the stripper; andmeans for flushing the spacebetween the bottom of the basket and thestripper, said means including a wash pipe having a discharge outletpositioned to direct a stream of water upwardly against the bottom ofthebasket, a fiuid motor carrying said wash pipe, said motor holding thewash pipe normally lowered so as not to interfere with reciprocation ofthe basket but adapted to raise said pipe to position the dischargeoutletthereof in proximity tothe bottom of the basket, an annular groovein the under surface of said bottom positioned to receive a stream ofwater from said wash pipe, and a plurality of passages leadingfrom said16 groove: to thespace: between the bottom oflthe basketiand saidstripper.

10. A centrifugingapparatus comprising a centrifuge basket; a stripperwithin and snugly fite ting said basket; valve-controlled means forcharging material tobe centrifuged to said hasket; valve-controlledmeans for introducing a wash liquid into said basket; means including avalve-controlled wash pipe for introducing a fiushing'liquid between thebottom of the basket and said stripper; means for rotating said basketand said stripper in unison; means for'moving said basket and'saidstripperaxially relative to each other; means for operatingsaid'valve-controlled charging means, said valve-controlled wash means,and said means for effecting relative axial movement between the basketand the stripper sequentially and in timed relation; and means foroperating said flushing means automatically after said'last-mentionedmeans has operated a' predetermined number of times;

11. In a centrifuging apparatus, a baskethaving a bottom and aforaminous annular side wall; a generally disk-shaped stripper memberwithin saidbasket and peripherally engaging the inner surface of saidannular side wall; means for rotatably driving the basket and stripperin unison; means for reciprocating the basket axially relative to thestripper; and means for flushing between the bottom of the basket andthe stripper, said means including'a wash" pipe havinga dis chargeoutlet positioned to direct the cleansing medium upwardly against thebottom of the basket, actuator means for said wash pipe, said actuatormeans holding the wash pipe normally lowered so as not to interfere withreciprocation of the basket but adapted to raise said pipe to positionthe discharge outlet thereof in proximity to the bottom of the basket,an annular groove in the undersurface of said bottom positioned toreceive cleansing medium from'said wash pipe, andat least one passageleading from said groove to the space between the bottom and saidstripper.

12. In a centrifuge apparatus, a rotatable centrifuge basket having anopen top provided with an internal, annular flange, a stripper withinand rotatable with said basket, means for effecting relative axialmovement between the basketand the stripper, a curb ring mountedindependently of the basket for sealing the rim of the basket, said curbring being formed with a radially outwardly facing annular shoulderarranged to project into and snugly fit the internal flange of thebasket and when so projected to'be spaced radially inwardly from theside wall of the latter whereby 'said shoulder and said wall definea'pocket within and immediately below the rim of the basket, saidpockets having liquid discharge openings extending radially outwardlyfor draining liquid therefrom.

13. In a centrifuge apparatus, a rotatable centrifuge basket having anopen top provided with an internal, annular flange, a curb ring mountedindependently of the basket for sealing the rim of the basket said curbring being formed with a radially outwardly. facing annular shoulderarranged to project into and snugly fit the internal flange of thebasket and when so projected to be spaced radially inwardly from theside wall of the latter whereby said shoulder and said wall define apocket within and immediately below the rim of the basket, said pockethaving liquid discharge openings extending radially outwardly fordraining liquid therefrom.

14. In a centrifuging apparatus; a rotatable centrifuge basket having anopen top provided with aninternaLannular flange, liquid dischargeopenings'in said basket, a stripper within and rotatable with saidbasket, means for effecting relative axial movement between the basketand the stripper, a curb ring mounted independently of said basket andpositioned to seat against the rim of the basket, said curb ringformedwith a radially outwardly facing annular shoulder arranged to projectinto and snugly fit the internal flange of the basketand when soprojected to be spaced radially inwardly from the latter whereby saidshoulder and said wall define a pocket with-.- in and immediately belowthe rim of the basket,

said pocket having liquid discharge openings extending radiallyoutwardly, for drainingliquid therefrom, the liquid discharge openingsof said pocket beingsubstantially larger and offering less resistancetopassage of liquids than the liquiddischarge openings of said basket.

In a centrifuging apparatus, a rotatable basket having an annular sidewall, a curb ring surmounting and in sealingrelation to said basket, anactuator for raising the curb ring from the basket, and members disposedexteriorly of and the basket, and means for disengaging the curb ringfrom 'the basketsimultaneously with said relative axial movementincluding a first support means connected to and extending downwardlyfromthe projecting portion of the curb ring exteriorly of the basket, 'asecond support means connected to the curb ring and extending downwardlytherefrom through the bottom of the basket, and means interconnectingsaid first and second support means for mutual operation.

17. In a centrifuging apparatus, a rotatable basket having an annularside wall, a curb ring surmounting and in sealing relation to saidbasket, a stripper in said basket, and means for disengaging the curbring from the basket including means disposed ,exteriorly of the,baskets interconnecting the stripper and the curb ring.

18. In a centrifuging apparatus, a rotatable stripper member, a curbring rotatable with said stripper member, a basket containing and 'ro-.tatable with said stripper, said curb ring and said basket being movableaxially relative to each other and said basket provided at therim'thereof with an inturned annular flange, said curb ring being formedwith an external annular shoulder which snugly fits and projects belowsaid flange in one position thereof relative to the basket, the

projecting portion of said shoulder and the side wall of the basketco-operating to define a pocket below said flange; and means fordraining liquid said housings being annular in form and provided with aninlet disposed in confronting relation to said discharge port, one ofsaid housings being stationary and normally arranged with its inlet inregister with said discharge port and the other of said housings beingvertically movableto position its inlet in register with said dischargeport and to close the inlet of said one housing.

20. In a centrifuging apparatus, a rotatably driven centrifuge basket, acurbv ring for sealing the rim ofthe basket and rotatable therewith, andanoverflow housing around said basket, said housing having an innerannular wall and proyidedwith a radially inwardly extending flangedisposed in alignment -with and spaced circumferentially from the rim ofsaid curb ring, said housing further provided above said flangewith anannular inlet, whereby overflow from the basket of material charged tothe basket. and falling on said curb ring is thrown radially outwardlybycentrifuge force from the curb ring andinto said housing. a

21. In a centrifuging" apparatus, a rotatably driven centrifuge basket,acurb ringlfor s aimg the rim of the .ba'sketand rotatable therewith, an

annular member surrounding and spaced circumferentially from said curbring, means supporting said. annular member in substantially the sameplane as the curb ring when the latter is in sealing relation with thebasket, and an overflowhousingaround said basket'and said annular memberhaving an annularinlet above said member, whereby overflowfrom thebasket or. material charged to the basket and falling' on curb ring isthrown radially'outwardly by centrifugal force from the curbring andinto, said housing.

22. In a centrifuging apparatus, a rotatably driven centrifuge basket, acurb ring for sealing the rim'of the basket, a housing around saidbasket' having an internal annular partition defining .concentricinnerand'outerchambers' and said partition provided at the upper edge thereofv'z-ith an inturned annular flange disposed in alignment with and inslight oircumferentially spaced relation to the periphery of said curbring when the'latter is in sealing relation to the basket, means forseparating the basket and said curb ring, and means for stripping solidsfrom the basket when the latter and the curb ring are sep arated, saidstripper being operable to spill solid material over the rim of thebasket and into the inner of said chambers, and said inturned annularflange serving as a baiiie to deflect liquid overflowing from the basketor falling onto said curb ring into the outer of said chambers and toprevent such liquid from entering the inner chamber and contaminatingsaid solid material.

23. In a centrifuging apparatus, a rotatably driven centrifuge basket, acurb ring for sealing the rim of said basket, means for effectingrelative axial movement between the curb ring and the basket, concentricinner and outer chambers around said basket, and an annular baffleextending transversely across said inner chamber and disposed inalignment with and in slight circumferentially spaced relation to theperiphery of the curb ring when the latter is in sealing engagement withthe basket.

24. In a centrifuging apparatus, a rotatably driven centrifuge basket, acurb ring for sealing the rim of said basket, means for effectingrelative axial movement between the curb ring and the basket, concentricinner and outer chambers around said basket, an annular bafiie extendingtransversely across said inner chamber and disposed in alignment withand in slight circumferentially spaced relation to the periphery of thecurb ring when the latter is in sealing engagement with the basket, andmeans for stripping solids from the basket, said stripper operable tospill solid material over the rim of the basket when the curb ring isseparated therefrom under the baffle and into the inner of saidchambers, said bafiie serving to deflect liquid overflowing from thebasket or falling onto said curb ring into the outer of said chambersand to prevent such liquid from entering the inner chamber andcontaminating said solid material.

25. In a centrifuging basket having a bottom, a stripper member snuglyfitting in and rotatable with said basket, means for effecting relativeaxial movement between the stripper and the basket, and means forflushing between the'bottom of said basket and said stripper including awash pipe having a discharge outlet positioned to direct a stream ofwater upwardly against said bottom, and an annular groove in the bottomof said basket positioned to receive said stream of water and providedwith a plurality of passages effecting communication between said grooveand the space between said bottom and said stripper.

26. In a centrifuging apparatus, a rotatably driven centrifuge baskethaving a bottom, a stripper fitting snugly within the basket, means foreffecting relative axial movement between the stripper and the basket,and means for flushing between the stripper and the bottom of the basketincluding a liquid-supply pipe for directing liquid against the exteriorside of the bottom of the basket, and means carried by the basket forcollecting liquid impinged thereagainst and defining a passage throughwhich liquid is discharged into the space between the bottom and saidstripper.

27. In a centrifuging apparatus, a rotatable basket having an annularside wall; a casing surrounding and rotatable with said basket, said 20casing cooperating with the side wall of the basket to define an annularcollecting chamber for material centrifuged from the basket and providedadjacent the bottom thereof with a discharge port; a pair of annularhousings surrounding said casing, each of said housings having anannular chamber provided with a bottom so as to be capable of receivingand accumulating material discharged from said collecting chamber, eachhousing also having an annular inlet communicating with said chamber andfacing in the direction of said discharge port; one of said housingsbeing stationary with its inlet in register with said discharge port;and means for moving the other of said housings vertically to bring itsinlet into register with said port and to close the inlet of saidstationary housing.

BRADLEY G. COX. THOMAS EVANS.

References Cited in the file of this patent UNITED STATES PATENTS

